Funds are requested for partial support of the 10th FASEB summer conference on Folic Acid, Vitamin B12 and One-Carbon Metabolism to be held July 31 to August 5, 2004 at Snowmass Village, Colorado. This conference offers a unique opportunity for productive, formal and informal interactions between clinician investigators, basic scientists and those involved in health and science policy. The participants represent a diverse and broad range of disciplines. The previous nine conferences, which met every second year, were fully subscribed. The current conference will be limited to 210 participants. The requested funds will support the attendance of graduate students, resident physicians, postdoctoral fellows and established national and international investigators. A detailed program, led by senior scientists, emphasizes the participation of junior scientists new to the field. The selected session and workshop topics cover the basic sciences and clinical research with particular emphasis on the interaction and potential synergy between the two. The specific session subjects include: (1) One Carbon Metabolism: Enzymology, Pathways, Compartmentation and Regulation, (2) One-Carbon Metabolism and Genetic Variation, (3) Methionine Metabolism: Regulation within the Integrated Pathway, (4) Pathophysiology of Homocysteine Toxicity, (5) One-Carbon Metabolism, Epigenetics and Development, (6) Inborn Errors of Cobalamin, Folate and Methionine Metabolism, (7) Chemical and Clinical Advancements in Cobalamin Transport and Metabolism, (8) One-Carbon Metabolism, Methylation and Neoplasia, (9) Folate Fortification: Assessment of Outcomes. The workshops will provide expert and current analyses of: (1) Folic acid, homocysteine and cardiovascular disease: results from clinical trials, (2) The clinical utility of holoTC as an early marker of vitamin B12 deficiency, (3) Hyperhomocysteinemia and cognitive dysfunction and (4) Pharmacogenomics. The format encourages discussions among the presenters and the fellows, residents and junior investigators in attendance. Similarly, the poster sessions also highlight the activities and needs of the younger participants.